80 THE WOOD. 



out to you a few objects which, if we had time, 

 would be well worthy of notice. First, look at 

 this Bramble leaf, which bears a light-coloured 

 mark, as if a little stream had meandered over it. 

 If you have never before been told the cause of 

 this, you will be interested in hearing it, for it 

 affords a remarkable example of that wonderful 

 instinct with which God endues even the smallest 

 of his creatures. A little fly deposits its egg be- 

 tween the upper and under skins of the leaf ; and, 

 when the young caterpillar is hatched, it moves 

 along still between the two skins, feeding upon the 

 substance of the leaf, and carefully turning back 

 when it arrives at the edge, so as never to break 

 the walls of its house. The insect eats more and 

 more in proportion to its growth ; hence the traces 

 of its journey gradually widen, until at last they 

 come to a sudden stop. Here the little devour er 

 undergoes a transformation, being converted into 

 what is called a pupa, or chrysalis, that is to say, 

 having arrived at a stage of its existence when it 

 neither moves nor eats, but is enclosed in a case, 

 and is to all appearance lifeless. After remaining 

 in this state for a time, it becomes a fly, and, having 

 again acquired the power of motion, liberates itself 

 from its hitherto secluded dwelling. 



Look again at the little green ball attached to 

 the under side of this Oak leaf! It is the habita- 

 tion of an insect which spends here a large portion 

 of its existence. And what a miserable existence ! 

 you will perhaps say. To be for a half of its life 

 confined within the limits of a single leaf, without 

 companions, and without the power of moving to 

 another place ! What can be more wretched ? I 



